1. Field of the Invention
This invention relates generally to obtaining useful work from the polytropic expansion of working fluids by reversible adiabatic expansion. More particularly it is concerned with a method of restoring such working fluids to their original thermodynamic conditions by means of an approximate isenthalpic compression, followed by heating, preferably by the use of ambient heat sources.
2. Description of the Prior Art
Useful work production by heating and vaporization of liquids, including cryogenic liquids under pressure, and thereafter expansion to exhaust vapors is well known. Most current techniques, however, particularly those designed to employ ambient heat sources, assume a continuous supply of working fluid from outside sources and are not concerned with recompressing and condensing exhaust vapors back to the liquid state in order to achieve a "closed" thermodynamic cycle.